植物雌激素槲皮素对非洲爪蟾生长和骨骼发育的影响

用两栖动物非洲爪蟾作模型动物,来揭示植物雌激素槲皮素对非洲爪蟾生长和骨骼发育的影响。非洲爪蟾从46/47期开始,分别暴露50μg/L,100μg/L,200μg/L槲皮素,直至变态后1个月。结果表明槲皮素处理一方面促进蝌蚪体重的增加,另一方面导致尾的畸形。200μg/L槲皮素还导致脊柱的畸形,表现为少一块脊椎骨。     

抗菌蛋白“N1235”对小麦赤霉病菌抗生活性测定及药效试验

采用PDA含药膜片法测定微生物发酵液抗菌蛋白“N1 2 35”对小麦赤霉病菌的抗生活性 ,结果表明对孢子及萌发菌丝具有致畸作用 ,表现为孢子芽管顶端膨大 ,菌丝体异常粗短 ,毒力回归方程 :y =7.1 471 - 0 .2 0 5 3x。母液稀释 5倍田间一次用药的防效为 43.6 3% ,两次用药的防效为6 1 .36 %。     

Current status and impact of mango malformation in Egypt

A survey was conducted in 1998 to determine the status and impact of mango malformation in Egypt. In the El Giza, Ismailîa and Sharkaia Governerates, disease incidence and severity ranged from 20 to 100% and from 5 to 60%, respectively. In contrast, 75 km to the south in the El Faiyûm Governerate, incidence and severity were lower, 3-5 and 0.1 to <1%, respectively. Based on these figures and recent production statistics, it is estimated that malformation causes losses in Egypt of at least E35 million/year. When malformation was managed in El Giza, Ismailîa and Sharkaia by removing affected vegetative and floral terminals, the mean disease incidence and severity were lower than in non-managed orchards (69 versus 29% and 29 versus 6%, respectively). Thirty-nine isolates of the pathogen, Fusarium mangiferae, recovered during the survey were sexually incompatible with the B, C and D mating populations of the Gibberella fujikuroi complex; 10 of these were also incompatible among themselves. Four vegetative compatibility groups (VCGs) were detected among 43 of the isolates from this and a previous survey. VCG was generally not correlated with farm, governerate or host cultivar, and in three instances, isolates from two different VCGs were recovered from the same tree. RAPD analyses divided isolates into two genetically distinct clusters: Group I contained isolates in VCGs 1, 2 and 4; Group II contained isolates in VCG 3. The VCG and RAPD data support the conclusion that isolates of the pathogen from the Nile Delta were probably responsible for the recent appearance of the disease in El Faiyûm.     

Physiological and biochemical changes with special reference to mangiferin and oxidative enzymes level in malformation resistant and susceptible cultivars of mango (Mangifera indica L.)

Changes in biophysical attributes, mangiferin and polyphenol oxidase (PPO), catalase and peroxidase activities in malformation resistant mango cultivar Elaichi were studied at various stages of flower development and compared with susceptible cvs. Amrapali, Beauty Mc-lin and Dashehari. Accumulation of mangiferin was maximum (96.0 and 108.0 mg g⁻¹ FW) in Elaichi prior to flower bud differentiation (September) and at full bloom (February), while these were minimum (59.0 and 74.0 mg g⁻¹ FW) in susceptible cv. Beauty Mc-lin. Mangiferin promoted vegetative growth and exhibited inhibitory role on the occurrence of malformation. It was also found that the resistant cultivar had highest activity of PPO as compared to susceptible ones. There was no significant difference in the enzymes catalase and peroxidase activity at early stage of flower differentiation but at flower bud burst stage the catalase activity was enhanced significantly in cv. Elaichi (25.28 unit min⁻¹ g⁻¹ FW) in comparison to Amrapali (16.20 unit min⁻¹ g⁻¹ FW), Beauty Mc-lin (18.39 unit min⁻¹ g⁻¹ FW) and Dashehari (17.50 unit min⁻¹ g⁻¹ FW). The resistant cultivar had high leaf temperature (30.30 °C) and diffusion resistance (476.14 m mol m⁻² s⁻¹) during the flowering but the rate of transpiration and relative humidity (RH) were high in susceptible cultivars. Results of the present study clearly indicate that level of mangiferin could be considered as a potential biochemical indicator for screening mango genotypes to malformation.     

莠去津对斑马鱼胚胎发育及幼鱼成活的影响

[目的]确定莠去津对斑马鱼生殖发育的毒性。[方法]从购自市场的斑马鱼中选取健康的雌鱼和雄鱼按1：2～1：3的比例进行交配产卵,分别用不同浓度的莠去津对斑马受精卵和平游后的幼鱼进行染毒试验,统计其孵化数和畸形数以及幼鱼死亡数。[结果]斑马鱼胚胎和幼鱼时莠去津毒性作用均很敏感,随着莠去津浓度的增加,斑马鱼胚胎孵化率降低,畸形率增加,幼鱼致死率增大。当莠去津高于30mg/L时,斑马鱼胚胎致死率和畸形率增加,当莠去津为50mg／L时胚胎出现全致死效应。斑马幼鱼对莠去津的毒性也很敏感,24h和48h的LC50值分别为36．25和22．89mg／L,在莠去津为50mg／L48h条件下,幼鱼产生全致死效应。[结论]该研究为莠去津的安全使用及淡水鱼的保护提供科学依据。